It is over a thousand years since the events of Double Planet, when a group of cosmonauts crashed a comet into the Moon, thereby bringing a potential life-supporting atmosphere to that desolate planet.
Tugela is a young girl who has grown up in the austere post-technological society that has settled there in that time, a society dominate by the all-powerful City and its insidious cult of the Eye. As the comets stopped coming, and the atmosphere became increasingly thin, the Priests' power grew with the claim that only their rituals could bring the comets back.
But a revolution is brewing among the Moon colony that aims to smash both the City and the poisonous stranglehold of superstition that has been holding it back for so long. Within this violent struggle, Tugela has a vital role to play. When she stumbles into a secret vital to the cause, she soon realises her destiny lies far beyond her homeland, beyond the deadly Forbidden Zone, perhaps even beyond the Moon itself...